/Engine/Source/Runtime/Engine/Public/ShadowMap.h
struct FSignedDistanceFieldShadowSample
float
Distance
Normalized and encoded distance to the nearest shadow transition, in the range [0, 1], where .5 is at the transition.
bool
IsMapped
True if this sample maps to a valid point on a surface.
float
PenumbraSize
Normalized penumbra size, in the range [0,1].